Only my sky texture is rendering
I'm not sure what you want, but it looks like you are using an alpha over node on two image without any transparency. This means only the image in the bottom input is used:



To do what I think you want to do, you need to render the sky as transparency. To do this, enable Transparent in render settings > Film:



You also seem to have deselected the layer with the model in the renderlayer. Ensure the layer you want is selected:



Once that's done, you should get a result like this (ignore the scale node, I needed that to scale my sky image to the render size)